The long-term aim of this proposal is to develop and validate an effective case management approach for people with dual diagnoses of substance abuse and chronic mental illness. New Hampshire's treatment program for dually diagnosed clients centers on the continuous treatment team-- a model which combines the principles of assertive case management and integrated treatment for substance abuse and mental illness. Continuous treatment teams will be compared with standard case management in community support programs. case management functioning will be assessed with several quantitative measures--a case manger service/activity log, MIS data, a measure of work environment, and case manager characteristics--as well as an ethnographic approach. This project will develop and maintain a continuous treatment team in the state largest city, Manchester, with the aid of an established public-academic liaison and an extensive training program for dual diagnosis clinicians. The first objective of the project is to decrease the problems most characteristic of dual diagnosis clients: alcohol and drug abuse, housing instability and homelessness, and institutionalization in hospitals and jails. A second objective is to determine whether good outcomes in these primary domains will be associated with more general improvements in symptoms, functional status, and quality of life. a third objective is to clarify pathways into and out of homelessness in this highly vulnerable population. A fourth objective is to identify the qualities of case management that are associated with successful engagement and treatment of dual diagnosis clients. Separate data analysis strategies will be applied to each of these objectives. The research evaluation design is a randomized clinical trial in Manchester and five other clinical sites, three of which are rural. A total of 270 consenting dual diagnosis clients will be randomly assigned to either continuous treatment teams or to standard case management. Study subjects will be interviewed with standard quantitative instruments at baseline and at six-month followup intervals for two years. A parallel ethnographic evaluation will occur at the Manchester site.